commit 94f950c4060cd9b1989c565284beb159b9705a50
author Jan Beulich <JBeulich@suse.com> Tue Jun 11 11:00:34 2013 +0100
committer David S. Miller <davem@davemloft.net> Thu Jun 13 01:25:24 2013 -0700
tree ad1501e540db23490a383b14a9af62f6db0ed27f
parent 99ffc3e74fb0d9d321d2f19c6021e0dbaff2f4b2

xen-netback: don't de-reference vif pointer after having called xenvif_put()

When putting vif-s on the rx notify list, calling xenvif_put() must be
deferred until after the removal from the list and the issuing of the
notification, as both operations dereference the pointer.

Changing this got me to notice that the "irq" variable was effectively
unused (and was of too narrow type anyway).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/xen-netback/netback.c

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 37984e6..8c20935 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -662,7 +662,7 @@
 {
 	struct xenvif *vif = NULL, *tmp;
 	s8 status;
-	u16 irq, flags;
+	u16 flags;
 	struct xen_netif_rx_response *resp;
 	struct sk_buff_head rxq;
 	struct sk_buff *skb;
@@ -771,13 +771,13 @@
 					 sco->meta_slots_used);
 
 		RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
-		irq = vif->irq;
-		if (ret && list_empty(&vif->notify_list))
-			list_add_tail(&vif->notify_list, &notify);
 
 		xenvif_notify_tx_completion(vif);
 
-		xenvif_put(vif);
+		if (ret && list_empty(&vif->notify_list))
+			list_add_tail(&vif->notify_list, &notify);
+		else
+			xenvif_put(vif);
 		npo.meta_cons += sco->meta_slots_used;
 		dev_kfree_skb(skb);
 	}
@@ -785,6 +785,7 @@
 	list_for_each_entry_safe(vif, tmp, &notify, notify_list) {
 		notify_remote_via_irq(vif->irq);
 		list_del_init(&vif->notify_list);
+		xenvif_put(vif);
 	}
 
 	/* More work to do? */